Micrometer gauge



Dec. 19, 1933. E J wlTCHGER ET AL 1,940,475

MI CROMETER GAUGE Filed May 20, 1952 [NVENTO]? EUGENE J W/TCHGEB 05 MFA]? 05BX 5 A TTORNEY Patented Dec. 19, 1933 UNITED STATES 1,940,475 MICROMETER GAUGE Eugene 'J. Witchger and Oscar A. Koebke, Sagihaw, Mich., assignors to Lufkin Rule 00., Saginaw, Mich., a corporation of -Michigan Application May 20, 1932. Serial No. 612,516 Claims. (01. 33-16 1) This invention relates to micrometer gauges of the class that employs ananvil-carrying yoke to which is secured a tubular barrel, a threaded micrometer spindle being screwed in the barrel and awear-compensating nut screwed on the,

spindle adjacent the barrel.

Such a micrometer gauge, as constructed hereg tofore, will wear away at the working faces of the screw threads of the spindle and also at the co-operating faces of the terminal threads in the barrel, especially after the gauge has been used for a long time to measure work-pieces of approximately one size. A greater or less amount of end play of the spindle develops as wear con- 1 tinues, the result being unreliable performance of the instrument when taking fine measurements. Such unreliability is due principally to maladjustment of the Vernier and uneven or unsatisfactory feel .of the gauge. 2o An object of this invention is to eliminate end play by providing automatic compensation for wear at the screw threads as thewear occurs.

The improvement, therefore, is characterized by having means associated with the compensating nut to cause the nutto automatically take up wear. Moreover, these take-up devices function to continually exert an amount of yielding pressure against the working faces of the screw threads on the spindle appropriate to produce correct feel of the spindle operating thimble or handle irrespective of ,thdamount of wear on the threads. .Adjustmentof theffeel can be made by these-devices withoutdisassembling the micrometer. i 3 v These advantages and certain others that will be set forth in the description are attained-by a novel structure and arrangement ofthe compensating nut, an adjustable sleeve carried by the nut, and a spring element that co-operates with the sleeve, all of which are hereinafterdescribed in detail, the several features of the invention being more particularly pointed out in the appended claims defining my invention. In the claims the essential elements are pointed 5 out, it'being understood, however, that the claims are not intended to be limited to the form of the parts illustrated and described further than.

Fig. 2 is an enlarged cross sectional view, broken away in part, taken on the line 2--2 of Fig. 3,

Fig. 3 is an enlarged View of the outer end of the handle. shown in Fig. l. r 1

i Fig. 4 is adetail, broken away, of the adjusting .5 sleeve for the compensating nut and its co-o'perating. compression spring. a

Fig. 5 is a detail, partly broken away, ofthe compensating nut.

. Fig; 6 is a similar detail of thethreadedib ishin 6,5

that constitutes the end of the barrel in the preferred form. 1 'i This invention is illustrated as. bein applied to a micrometer gauge of the ordinary time 90. sisting of a yoke or frame 1 upononearm of ,7 which is an anvil (not shown), the otherarm' carrying the usual internally threaded tubular barrel, 2, into whichthe micrometer spindle 3 is: screwed. Spindle 3 is rotated on the barrel by means of a thimble 4 that surrounds the bar- 7 rel in telescoped relation. Thimble 4 is fixed to spindle 3 by soldering at 5, or otherwise. A compensating nut 6 is threaded on spindle 3 adjacent a separable, internally. threaded end portion 7 of barrel 2, which is, in effect, a reduced .8 end portion of the barrel. Nut 6 is interlocked with the end 7 of-the barrel in such a way that itcan not be rotated,.but is capable ,Qf endwise movement relative to the barrel." The int rlocking arrangement is preferably of the nature of a jaw clutch arranged so that its elements can be engaged onlyv when the threads of the nut and of the barrel are-positioned for helical continuity. 'With this arrangement it isimpossible to inadvertentlyassemble the barrel and the spindle and .9 the compensating nut in any way except in proper working relationship. In the form illustrated this clutch consists of a pair of notches, 8, in the ends of the barrel'and a pair of cooperating lugs, 9, that project from the end of nut 6 and are adapt- .95

ed to be received in. the notches 8 when the nut and barrel are assembled, as shown in Fig.2 and Fig. 3. In the form shownthese clutch elements are offset with respect to the diametrical line of.

the barrel-so that they can be assembled in one 100.

position only, that is, when the threads 7 ,of

the barrel and the threads ofnut 6 are in helical continuity, permitting the spindle to be screwed through both the barrel and thecompensatin nut asif these two parts were-integral and' were provided with a single continuous screwthread. A yieldable compression spring 10 or its equiyalent is used to urge thenut 6 longitudinally away from the end 7 of thebarrel totheright in Fig.

1', and so keeps the threaded end of the spindle normally urged lengthwise away from the yoke.

. During the taking of a measurement the working faces of the screw threads on the spindle 3 and of the threads on the end'portion 7 of the barrel are kept normally in yielding contact with each other at 11 and endwise play of the spindle toward theoright, Figs. 1 and 3, is prevented. A

preferred arrangement of spring 10 is shown in Fig. 3, which also shows means whereby the amount of its compression can be varied to adjust the sensitiveness or feel of the instrument during the taking of measurements.

Nut 6 is externally threaded at 12. A sleeve 13, internally threaded at one end, 14., is screwed 1 on the nut for endwise adjustment with respect to the nut. Athreadless portion 15 ;of sleeve 13 telescopes with and surrounds the reduced end portion 7 of the barrel2; Extension 15 of sleeve 13 is formed at its end to present a counterbore 16. Spring 10 is received in the counterbore 16 and so is'enclosed in-an annular chamber. It is prevented from coming into contact with threaded spindle 3, likewise is kept from contact with the inner wall of the tubular thimble 4 that surrounds the barrel. Spindle 3 and thimble l are thus assured of free rotation and spring 10 V is not subjected to wear, neither can it introduce any frictional action that might interfere with the feel of the'instrument.- Sleeve 13 is preferably formed with a longitudinal slit, as shown at 17 in Fig. '4, to-keep it from binding around the nut 6. A hole 18 to receive a small spanner wrench is provided in the sleeve to eifect its longitudinal adjustment and to regulate the compression of spring 10.

Spring 10, received in the counterbore of the sleeve, has its end seated upon. an annular shoulder or abutment-19 on barrel 2.

The-threaded 'end portion 7 of barrel 2 may be renewed easily if damaged, being press-fitted into a counterbore 20 of the barrel.

For the purposes of our invention asclaimed it is immaterial whether the barrel 2 is made in two parts, 2, 7 shown in Fig. 3 or in one piece.

Thimble 4 maybe made in two parts, as is shown in Fig. 3, one part being in tubular cap member '21 which is internally threaded at 22, the other part being tubular portion 23 externally threaded at.24 and screwed into the cap member 21. The describeddetails 21, 23 of thethimble structure' are also optional, but in practice these structures are considered'preferable, Y An advantage of the structure herein shown and described is that all necessary adjustments for compensation of' wear and the adjustments for feel can be made without requiring the operator to use more'than ordinary care, and without disassembling the instrument. With this adjustable arrangement the parts can not be assembled' in any way except the right one. these respects the present invention differs materially from those previousdevices in which ex-.

, treme care must be taken duringthe operation 'of adjusting, to turn a threaded adjusting elespindle. To meet that requirement sleeve 13 is screwed along nut 6 until its end portion 16 meets abutment 19 and thrusts the spindle to the right, Fig. 3, urging working faces of the spindle threads against the threads of the barrel, as at 11, sufficiently to give the desired feel. When sleeve 13 is against abutment 19 there is no possibility of end play of'the spindle in either direction.

Thus the operator has two alternative ways to compensate for wear and adjust the feel. Spring 10 can be utilized in the manner first described herein, or else sleeve 13 can be brought into actual contact with abutment 19. In either case wear is compensated for. Using spring 10, further wear is automatically corrected but a small amount of back lash is sensed if the spindle is pushed toward the yoke. If the sleeve is screwed into contact with abutment 19 no back lash will be present and in case he prefers not to use spring 10 subsequent wear can be taken up by periodic adjustment. In all cases, however, the feel is controlled by adjusting sleeve 13 in relationto nut 6 and abutment 19 as distinguished from former practice wherein the feel had to be regulated by turning the nut in relation to the barrel, which had the undesirable effect of distorting the helical continuity of the thread.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. A micrometer gauge having in combination,

a tubular internally threaded barrel with an end portion of reduced external diameter presenting an abutment, a threaded micrometer spindle,

elements are in mutually non-rotatable relation but are capable of relative movement 'endwise,

7 said interlocking elements being mounted on the barrel and spindle so that they can be interlocked only when the threads of the nut and of the barrel are in helical continuity, a longitudinally slitted adjusting sleeve surrounding said nut in threaded engagement therewith, a portion of said sleeve surroundingan endof said barrel and formed with a counterbore, and a helical compression spring received in said counterbore and seated upon the abutment of said barrel, whereby the working-faces of the threads ofthe spindle are kept yieldinglypressed against 'co-operating faces of the threadsof said barrel, the arrangement being such that'rotation of'said adjusting sleeveca uses var'iabl'edegrees of compression of said spring and thereby adjusts the feel of said micrometer gauge du'ring'the taking of measurements. i

'2. A micrometer gauge having, in' combina- 'j tion, a tubular internally threaded barrel, a threaded micrometer spindle adapted m be screwed into saidbarreh'a compensating nut adapted to be threaded on said spindle, interlocking elements 'operatively connecting said barrel and said nut and arranged so that th'e eleof the nut are kept yieldingly pressed against 00- 4. A structure as set forth in claim 3 wherein the tubular sleeve is provided with an internal thread screwed on said nut and is formed with a counterbore within which said spring is enclosed.

5. A micrometer gauge having in combination j 3 a barrel, a screw threaded therein, and a nut on the screw adjacent the barrel, elements operatively connecting the barrel andrnut, said ele-,

ments being arranged for relative endwise movement and for. interlocked engagement against relative rotation, and a sleeve surrounding said nut and longitudinally adjustable thereon and an abutment on the barrel positioned to be engaged by said sleeve, the sleeve and abutment constituting means whereby to adjust for endwise looseness in the threads by forcing apart the said nut and barrel. v

EUGENE J. WITCHGER. OSCAR A. KOEBKE. 

